Boiler Mountings and Accessories (Safety and Control Devices)
In dairy processing plants, boilers are used to generate steam for various operations such as pasteurization, sterilization, cleaning-in-place (CIP), and heating. To ensure safe, efficient, and smooth operation, every boiler must be equipped with specific mountings and accessories.
These can be broadly divided into:
- Boiler Mountings – Essential safety and control devices mounted on the boiler.
- Boiler Accessories – Additional equipment to improve efficiency and performance.
✅ A. Boiler Mountings (Safety and Control Devices)
Boiler mountings are the mandatory components attached directly to the boiler shell to ensure safe operation, control of steam generation, and protection of the boiler from accidents.
1. Safety Valve
- Function: Automatically releases steam when the internal pressure exceeds the safe limit.
- Prevents boiler explosion due to over-pressure.
- Common types: Spring-loaded safety valve, lever safety valve, dead weight valve.
2. Water Level Indicator
- Function: Shows the actual water level inside the boiler.
- Operators use it to maintain the water level within the safe limit.
- Usually made of a glass tube fitted vertically on the boiler shell.
3. Pressure Gauge
- Function: Indicates the internal steam pressure of the boiler.
- Calibrated in units like kg/cm² or bar.
- Helps operators monitor pressure and take action before it becomes unsafe.
4. Fusible Plug
- Function: Acts as a safety device to prevent boiler damage when water level falls too low.
- The metal inside the plug melts at a certain temperature, creating a hole through which steam/water escapes and extinguishes the fire.
- Prevents overheating and bursting of the boiler.
5. Steam Stop Valve
- Function: Controls the flow of steam from the boiler to the steam line.
- Allows shutting off the steam supply to process equipment when needed.
6. Feed Check Valve
- Function: Controls the entry of feed water into the boiler shell.
- Prevents the backflow of steam or hot water into the feed line.
7. Blow-off Valve (Blowdown Valve)
- Function: Removes sediments and impurities from the bottom of the boiler.
- Helps maintain clean water inside the boiler to prevent scaling and corrosion.
8. Manhole and Mudhole
- Function: Provide access to the interior of the boiler for inspection, maintenance, and cleaning.
- Mudhole is located at the bottom for removing sludge.
9. Air Vent Valve (Boiler Vent)
- Function: Removes air trapped inside the boiler during initial startup or shutdown.
- Helps prevent air binding and ensures complete water filling.
10. Economizer Safety Valve
- Fitted separately on the economizer (if present).
- Protects the economizer from excess pressure buildup.
✅ B. Boiler Accessories
These are auxiliary equipment attached to the boiler to increase efficiency, reduce fuel consumption, and improve steam quality. They are not mandatory but highly beneficial.
1. Economizer
- Function: Pre-heats the feed water using the flue gases coming out of the boiler.
- Saves fuel and increases thermal efficiency.
- Reduces the temperature difference between feed water and boiler water.
2. Air Preheater
- Function: Uses hot flue gases to heat the air before it enters the combustion chamber.
- Promotes better fuel combustion and reduces fuel consumption.
3. Superheater
- Function: Increases the temperature of steam beyond the saturation point by removing moisture content.
- Produces dry and high-pressure steam used in turbines or sterilization.
4. Feed Pump
- Function: Pumps water from the feed tank into the boiler under pressure.
- Can be mechanical, rotary, or electrically driven.
5. Steam Separator
- Function: Removes entrained water particles from steam to ensure dry steam supply.
- Prevents damage to steam turbines and improves efficiency.
6. Steam Trap
- Function: Automatically removes condensate (water) from steam pipelines without allowing steam to escape.
- Maintains thermal efficiency and avoids water hammer effects.
7. Deaerator
- Function: Removes dissolved gases (like oxygen and carbon dioxide) from feed water.
- Prevents corrosion inside the boiler and pipes.
8. Chimney or Stack
- Function: Discharges exhaust gases from the combustion chamber into the atmosphere.
- Provides natural or forced draught for better combustion.
Comparison Between Mountings and Accessories
| Feature | Boiler Mountings | Boiler Accessories |
|---|---|---|
| Nature | Essential for safety and operation | Optional for efficiency improvement |
| Location | Mounted directly on boiler shell | Attached to boiler or flue gas path |
| Examples | Safety valve, pressure gauge, blow-off | Economizer, superheater, feed pump |
| Regulatory Requirement | Mandatory as per boiler rules | Not mandatory but highly recommended |
Conclusion
Boiler mountings and accessories play a critical role in the safety, control, and efficiency of steam generation in dairy plants. While mountings like safety valve, water level indicator, and pressure gauge ensure safe operation, accessories like economizers, superheaters, and feed pumps help in saving fuel, improving performance, and enhancing productivity.
For smooth and sustainable dairy plant operations, proper maintenance and monitoring of both mountings and accessories are essential.